During the coming year a third group of infants will be born to those female rhesus monkeys that were exposed to diets containing 2.5 and 5.0 ppm PCB for 18 months two years previously. Our primary interest will be to determine the length of time following PCB exposure necessary for normal infants to be born to these mothers. Those infants born during PCB exposure and those conceived 1 year following the discontinuation of PCB exposure have shown definite signs of intoxication. In addition to the clinical and biochemical assays, psychological evaluations will be conducted on these infants. In order to further clarify the toxic effects that arise in nonhuman primates that are being exposed to levels of PCB which may occur in selected populations in the United States, the groups that have been given diets containing 0.5 and 1.0 ppm three times weekly will be evaluated through a second gestation. In this experiment, accumulation of PCB in the adult tissues as well as the infants will be determined. In addition, emphasis will be given to potential cumulative effects that these PCBs may have on the general body health and their reproductive capabilities. There will also be a thorough evaluation of the fetal and neonatal development of the offspring of these chronically exposed animals.